The present invention relates to an apparatus for converting mechanical rotation into pressure energy and/or vice versa.

In many contexts, it is desirable to be able to convert energy in a manner which is as versatile, safe and loss-saving as pos- sible. For example, it is desirable to be able to convert pressure into rotation and vice versa. To gain access to as many sources of energy as possible, it 1s appropriate to allow the energy to expand for generating a pressure which, 1n Its turn, is converted into ro¬ tation. Apart from electric motors, most types of motors and engines operate according to such a principle, and it is normally desirable to be able to optimate such energy conversion. Naturally, this con¬ version is not restricted to motors and engines, but may be just as applicable in the context of pumps, in which it is desirable to con¬ vert mechanical rotation into, for example, hydraulic pressure. The advantages inherent 1n hydraulic systems are legion. For example, liquid 1s used as a transmission medium, the hydraulics system not only transmits force but may also be designed as a force booster, the liquid is highly mobile, the liquid is not compressed to any ap¬ preciable degree, and the direction of flow of the liquid may be modified in fractions of a second. Furthermore, high pressure can be imparted to the liquid, which entails small components for heavy- duty work, whereby the effect output per component will be superior to all other forms of transmission, and 1t is easy to control and multiply forces, since the liquid is not readily compressible.

The task forming the basis and object of the present ^" invention is to realise a simple and reliable apparatus for satisfying the above-outlined desiderata as expressed 1n this Art.

This task is solved and this object 1s attained according to the present Invention 1n that the apparatus disclosed by way of in¬ troduction 1s provided with a piston disposed 1n a first cylinder, the piston being provided with at least one stub shaft which extends radially from the piston through an axial groove-like recess in the wall of the cylinder and which extends through the cylinder wall in- to a groove inclined in relation to the recess for guiding the stub shaft in a periodic curve, the cylinder chamber on one side of the piston being connected to an energy source or energy recipient, and the cylinder chamber on the other side of the piston being connected to another and/or the same energy source or energy recipient. In one embodiment of the present invention, the piston is provided with registering, counter-directed stub shafts each for their groove-like recess in the cylinder wall, while the groove for guiding the stub shaft along a periodic curve is disposed in a further cylindrical wall. This further cylindrical wall forms a second cylinder which is coaxial with the first cylinder. The groove in the second cylinder lies in an inclined plane whose central axis of inclination is lo¬ cated substantially in the axis through the stub shafts of the pis¬ ton and between the ends of the axial grooves in the first cy¬ linder. The groove is of such configuration as to give an ellip- tical, monoperiodic curve. In a further embodiment of the present invention, the groove 1s of such configuration as to give a sinus¬ oidal, duoperiodic curve. In yet a further embodiment of the present invention, the groove 1s of such configuration as to give a para¬ bolic, duoperiodic curve. In one embodiment of the present inven- tion, several pistons may be disposed in one and the same cylinder, in which event the pistons are pivotally offset in relation to one another. Suitably, the pistons are three in number and the pistons are offset through 120 degrees in relation to one another. The pis¬ tons are each provided with their separate and discrete inner cy- under, with inlets and outlets for the cylinder chambers on either side of the pistons, and a common outer cylinder. The pistons may, here, be two in number and are offset through 90 degrees in relation

to one another, the pistons having a common cylinder chamber which is located between the pistons. The stub shafts on the pistons are provided with bearings, preferably roller bearings, for both the re¬ cesses in the inner cylinder and the grooves in the outer cylinder. An apparatus according to the present invention will essen¬ tially satisfy the desiderata disclosed by way of introduction, and will afford many advantages. The apparatus according to the present invention makes possible an extremely simple and symmetrical con¬ struction, with few fixed parts and few moving parts. In an appar- atus according to the present Invention, the possibility is created for a large part of operative volume. Furthermore, the weight of the apparatus can be kept to a minimum, with very slight reciprocating mass. An apparatus according to the present invention will be of double-action and there will be no need for steadying effect, since one of the cylinders acts as a flywheel. Since the cylinder can ro¬ tate, this makes for extremely simple intake and discharge. In a very simple manner, the groove in the outer cylinder may be given such configuration that the curve of movement of the piston may be adapted to the desired driving method, as well as stroke length, combustion characteristics etc. Furthermore, an apparatus according to the present invention is readily counterbalanced and equilib- riated by the utilisation of various combinations.

An apparatus according to the present invention not only makes possible an extremely simple conversion of pressure into rotation and vice versa. Thus, the invention also makes possible - in that the apparatus is provided with two separate and discrete chambers - a two-circuit system and rotation by means of two different media under pressure, simultaneously or individually. Moreover, two vol¬ umes of equal size may be pumped simultaneously, and a first medium may be pumped by a second medium under pressure. This entails trans¬ formation between pneumatic and hydraulic systems. Finally, the pre¬ sent invention makes for mechanical rotation, and pumping of one me¬ dium by the intermediary of a second medium under pressure, as well as pressure-positive operation and/or rotational operation of a pump.

The present invention will be described in greater detail below with reference to the accompanying Drawings.

In the accompanying Drawings:

F1g. 1 1s a schematic perspective view of parts for illus- trating the basic principle of one embodiment of the present in¬ vention;

F1g. 2 is a similar perspective view to that of Fig. 1 for il¬ lustrating the basic principle of a further embodiment of the pre¬ sent invention; Fig. 3 is a similar, but exploded, perspective view to that of Fig. 2;

Figs. 4-7 are schematic perspective views of different embodi¬ ments of the present invention;

Fig. 8 is a schematic perspective view of a fundamental oper- ating principle according to the present Invention;

Figs. 9-11 are schematic views for illustrating different structural solutions for inlets and outlets;

Fig. 12 shows a number of similar schematic sections through one embodiment according to the present invention, for illustrating an internal combustion engine principle;

Figs. 13-15 show, on a larger scale, schematic partial sections for illustrating different stub shaft bearings;

Figs. 16 and 17 are schematic views for illustrating sealings at the inner grooves; Fig. 18 is a schematic perspective view of one embodiment of the present invention with a axially elongate piston;

Fig. 19 is a schematic perspective view, partly in section, of one prototype according to the present invention;

Fig. 20 is a side elevation, partly in section, of an apparatus according to a further embodiment of the present invention;

Fig. 21 1s a cross-section taken along the line XXI-XXI in Fig. 20; and

Fig. 22 is a cross-section taken along the line XXII-XXII in Fig. 20.

The principle of an apparatus according to the present in¬ vention is illustrated 1n Fig. 1. For illustrating this principle, only three mutually movable parts are required which, in Fig. 1, consist of a piston 1, an Inner cylinder 2 and an outer cylinder 3. The piston 1 has a radial stub shaft 4. The stub shaft 4 extends through an axial slot 5 in the inner cylinder 2 and at least into a groove 6 in the outer cylinder 3. The groove 6 lies in a plane which is inclined in relation to the longitudinal axes of the cylinders 2 and 3 and the piston 1, the central axis of inclination of the in- dining plane about which the plane inclines being located in the longitudinal axis of the stub shaft 4, when the stub shaft is lo¬ cated substantially centrally between the ends of the slot 5. When the inner cylinder 2 rotates 1n relation to the outer cylinder 3, the stub shafts 4 will be caused to follow a monoperiodic elliptical curve. If the cylinder chambers on either side of the piston 1 are enclosed and provided with inlets and outlets, rotation of the inner cylinder 2 can, obviously, be converted into pressure energy in the two cylinder chambers, which can be transmitted to a suitable med¬ ium, for example hydraulic oil. It is also possible to convert pres- sure energy from the two cylinder chambers into rotational energy in the inner cylinder 2.

This illustrated principle for converting rotational energy in¬ to pressure energy and vice versa may be physically applied in a plurality of different embodiments which will be illustrated herein- below, the same reference numerals being applied to the same or cor¬ responding parts in the different Drawing Figures.

The embodiment, illustrated in Figs. 2 and 3, of the principle for an apparatus according to the present invention, differs from that of Fig. 1 1n that the groove 6 1s designed such that the stub shafts 4 move along a duoperiodic sinus curve when the inner cy¬ linder 2 rotates in the direction of the arrow 7 in Fig. 2. In this context, the piston 1 and the stub shafts 4 will move between the ends of the slots 5 in the Inner cylinder 2 in accordance with the arrows 8 in Fig. 2 . In the embodiments illustrated In Figs. 1-3, the outer cylinder 3 is coaxial with the inner cylinder 2, while there is, naturally, nothing to prevent the outer cylinder 3 from being made linear in

accordance with the embodiment Illustrated in Fig.4. Otherwise, the remaining parts In the linear embodiment are of substantially the same construction as the previously-described embodiments. However, it should be observed that the outer contour of the inner cylinder 2 is suitably of the same cross-section as the Inner contour of the outer cylinder 3. The outer contour of the outer cylinder 3, may, in principle, be given any desired optional configuration.

Fig. 5 illustrates a rather special embodiment in which the in¬ ner cylinder 2 with the piston 1 1s disposed about the outer cy- Under 3, and the piston 1 is provided with a single stub shaft 4. When the piston 1 is provided with but a single stub shaft 4, as shown in Fig. 5, it is necessary that the resultant of the pressure forces on the piston 1 and the resultant of the reaction forces on the stub shaft 4 be of the same effective linear appearance, since otherwise serious problems of imbalance may arise. Fig. 6 also shows an embodiment in which the inner cylinder 2 and the piston 1 are disposed on the outside of the outer cylinder 3.

Fig. 7 illustrates an embodiment in which the outer cylinder 3 is of split construction, with two cylinders 3 located each at its stub shaft 4 and each with its respective groove 6. The cylinders 3 may rotate in the same direction or in opposite directions.

Fig. 8 illustrates a number of modifications of the fundamental operative principle for converting pressure into rotation and vice versa. It will be apparent from Fig. 8 that it is possible to rea- use a rotation R by means of two different pressure media Tl and T2 simultaneously or one-at-a-time. Furthermore, it is possible to pump two volumes of equal size simultaneously, which may be appropriate in, for example, the mixture of two substances, or when it is desir¬ able that two hydraulic cylinders move an equal distance, or further conceivably in such applications as cardiac implants and artificial hearts. Similarly, the one medium Tl may pump the second medium T2, whereby the principle may be applied for transformation between pneumatic and hydraulic systems. Moreover, for example the medium Tl may give rise to both rotation R and pump the second medium T2. Furthermore, a pump can be driven by means of pressure and rotation simultaneously or by these means individually.

In the previously-described embodiments of the present inven¬ tion, the piston 1 will execute, 1n principle, two piston cycles per revolution of the Inner cylinder. In the event of the present Inven¬ tion being applied to a four-stroke Internal combustion engine, such an engine will not require a crankshaft, will not require a cam¬ shaft, will not require complex valve control systems, will not re¬ quired distributor, balancing weights, flywheel, crank arms etc. Since ignition 1s effected only once per revolution, the ignition system can be made extremely simple and exact, because the inner cy- Under 2 functions as a rotor, irrespective of whether conventional or electronic Ignition is employed.

Both intake and discharge can be made extremely simple and ex¬ act, as illustrated in Fig. 9. Clearly, for controlling conventional valves, only fixed cams are required which rotate with the inner cy- under 2. It is also possible to employ the same valve or valves for both aspiration and exhaust, which makes for considerable operative optimation. Various types of throttle or choke feeds are also con¬ ceivable, as illustrated in Figs. 10 and 11.

Fig. 12 illustrates a two-cylinder internal combustion engine which operates on the four-stroke principle, the inner cylinder 2 being provided with two double-action pistons 1 which each operate in their cylinder chamber, although the inner cylinder 2 is common to both of the chambers. The space between the pistons 1 is separ¬ ated by a partition 9. Naturally, it is of vital importance for overall operative mode success that the bearings of the stub shafts 4 in the slots 5 and grooves 6 be of the ultimate conceivable type, since both degree of efficiency and wear will be greatly dependent upon this selection. In the slot 5 in the inner cylinder 2, it may be appropriate to em- ploy hydrostatic lubrication in slide bearings, since the stub shaft 4 stops abruptly and changes direction at the end positions in the slots 5. In the groove 6, roller bearings may be appropriate, al¬ though this may give rise to a problem, since the stub shaft 4 oper¬ ates alternatingly against the edges in the grooves 6, in which event the direction of rotation of the bearings will be reversed, as illustrated in Fig. 13. In this case, it 1s necessary to apply the solution illustrated in F1g. 15 with counter-rotational roller bear¬ ings. Fig. 14 also illustrates such a solution. This double bearing

provision is solved with the bearings displaced either axially or radially, as Illustrated 1n the two Drawing Figures 14 and 15. The return in the groove 6 may be solved by the employment of running rollers on the roller bearings with a slight axial curvature on the outer ring. The roller races of the groove 6 need not necessarily be at right angles to the cylinder shafts, it being eminently con¬ ceivable to provide specifically-designed races which absorb the centrifugual force to which the bearings are exposed. It is also possible to dispose the bearings of the stub shafts 4 in their oun- ting proper on the piston 1.

In the embodiments of the present invention described in the foregoeing, there naturally occur sealing problems between the inner cylinder 2 and the outer cylinder 3, because of the extant slots 5 and grooves 6. As has been pointed out above, the grooves 6 may also consist of slots. Such sealing problems may be resolved in a rela¬ tively simple manner by displacing, by the intermediary of a piston rod, the slots 5 and the piston stub shafts 4 outside the pressure chamber proper. In this case, the stub shafts are located on the end of the piston rod. However, using this solution to the sealing pro- blem, the cylinder chambers on both sides of the piston 1 will not be of equal size and, as a result, the construction in total will be at least twice as large and, moreover, will be asymmetric. Another manner of solving the sealing problem is illustrated in Figs. 16 and 17, in which seals 10 are disposed about the slots 5 in the inner cylinder 2 and above and below the stub shafts 4, these seals 10 following the movements of the stub shafts 4 and the piston 1. The pressure medium which strives to force Its way out from the cylinder 2 through the slots 5 will be entrapped and enclosed by a rectangle of seals 10 which seal against the outer cylinder 3, as is apparent from Figs. 16 and 17. Fig. 18 also illustrates a method of solving the sealing problem-structure, this being effected quite simply in that the piston 1 is given slightly greater axial length than the slots 5. In F1g. 5, it 1s also illustrated that the piston 1 is pro¬ vided with some type of piston ring 11, and such rings may naturally be provided in the desired number and desired type and dimension.

In order to achieve a uniform and even flow or uniform and even rotation, it may be appropriate to provide a number of pistons 1 in axial sequential relationship in one and the same inner cylinder 2, or possibly a number of inner cylinders 2 in mutual sequential re- lationship. Naturally, other interconnection alternatives are also conceivable.

Fig. 19 Illustrates one embodiment of the present invention with three pistons 1 which are displaced through 120 degrees in re¬ lation to one another. Furthermore, the Inner cylinder 2 is, at its ends, Interconnected to gudgeon shafts 12 and 13 and an outer cy¬ linder 3 is disposed coaxlally outside the Inner cylinder 2, the outer cylinder being provided with inlet means for a first pressure medium Tl and inlet means for a second pressure medium T2, the out¬ lets being not shown on the Drawings but being displaced through 90 degrees in relation to the Inlets. It will be further apparent from Fig. 19 that the pressure media Tl and T2 are supplied to the cy¬ linder chambers by the intermediary of choke or throttle arrange¬ ments. In the embodiment Illustrated in Fig. 19, there is provided a partition wall for dividing off the cylinder chambers between the pistons. In this embodiment, the grooves 6 in the outer cylinder 3 are three in number and are parallel, and also form duoperiodic si¬ nus curves. It has also proved to be appropriate to substitute the sinusoid curves with parabolic curves. In all probability, this em¬ bodiment would give an extremely uniform flow on uniform rotation, and vice versa, and would be equilibriated to a substantial degree. It is also possible to rotate the grooves 6 instead of the pistons 1, or both.

Figs.20-22 show a further embodiment of an apparatus according to the present invention, which 1s provided with two gudgeon shafts 12 and 13 which are connected to the inner cylinder 2 by means of keyways 14 and keys 15. An outer cylinder 3 is disposed about the inner cylinder 2 and 1s journalled by means of roller and ball bear¬ ings 16, at least at the ends of the inner cylinder 2. In the inner cylinder 2, there are disposed two pistons 1 with a common cylinder chamber centrally between the pistons 1 and each with their own end cylinder chamber. The outer cylinder 3 is provided with communi¬ cation members 17 and keys 18 and keyways 19 orientating the parts of the outer cylinder 3 about the inner cylinder 2.

The inner cylinder 2 also Includes two slots 5 for the one piston 1 and two slots 5 for the second piston 1, while grooves 6 are provided In the outer cylinder 3. The pistons 1 display double, counter-directed stub shafts 4A and 4B, which present roller bear- 1ngs 20A and 20B for the slots 5 and roller bearings 21A and 21B for the grooves 6. The pistons 1 with the stub shafts 4A, 4B are rotated through 90 degrees 1n relation to one another. In the outer cylinder 3, there are further provided Inlets 22 and outlets 23 for the dif¬ ferent cylinder chambers. Elongate apertures 24 are provided in the inner cylinder 2 for cooperation with the inlets 22 and the outlets 23.

The various parts cooperate in the same manner as described in conjunction with the previously-disclosed embodiments. However, it should be pointed out that, in order to attain as uniform a flow or as uniform a rotation as possible, a plurality of the units illus¬ trated in Figs. 20-22 may be axially interconnected to one another, or also in lateral relationship to one another, with the assistance of suitable transmission means between the gudgeon shafts 12 and 13.